diff --git a/QUSTOJ/1899.cpp b/QUSTOJ/1899.cpp
new file mode 100644
index 0000000..a32f7ff
--- /dev/null
+++ b/QUSTOJ/1899.cpp
@@ -0,0 +1,42 @@
+#include <cstdio>
+#include <cstring>
+#include <cstdlib>
+#include <algorithm>
+using namespace std;
+
+struct btree
+{
+    btree* l;
+    btree* r;
+    char v;
+};
+
+btree _node;
+btree* root=&_node;
+
+int counter=0;
+
+void deal(btree* n)
+{
+    scanf("%c",&n->v);
+    if(n->v=='#')
+    {
+        n->l=n->r=NULL;
+        return ;
+    }
+    else
+    {
+        n->l=new btree;
+        deal(n->l);
+        n->r=new btree;
+        deal(n->r);
+        if(n->l->v=='#'&&n->r->v=='#') ++counter;
+    }
+}
+
+int main()
+{
+    deal(root);
+    printf("%d\n",counter);
+    return 0;
+}